Permanent wave heater



March 31, 1942. I c. STEARNS 2,278,335

' PERMANENT WAVE HEATER Fil d Sept. 21, 1940 2?? J1 J7 fizz/erzi or'" JEEP r13 C 55ar'f26 Patented Mar. 31, 1942 PERMANENT WAVE HEATER Harry 0. Stearns, Chicago, 111., assignor, by mesne assignments, to Products Development, Inc., Chicago, Ill., a corporation of Illinois Application September 21, 1940, Serial No. 357,773

1 Claim.

The present invention relates to heaters that are used in connection with waving human hair. These devices, since they are used close to the human head, need to be of light construction and yet capable of giving continuous service under conditions where the operators are not familiar with the construction of electrical devices.

It is one purpose of the present invention to provide a device of this character which is particularly adapted to display to the operator, in an unmistakable fashion, whether or not there is anything wrong with the electrical circuit by which the heater is heated. In this connection, it is contemplated to provide a device wherein a portion of the heating element is made visible at a convenient spot on the heater so that the operator may see directly whether or not the heating element is actually in operation.

It has been found necessary in order to obtain a commercially practical and simple construction for the broad purpose hereinbefore mentioned, without at the same time providing a danger spot on the heater, where excessive heat might burn the operator or customer, to construct the heater unit so as to disclose an active part of the heating element to the eye of the operator with suflicient light, due to the heat of the element, as to make it clearly visible, yet maintaining at the same time adequate insulation to prevent the high heat of the element from providing a hot spot that could readily come in contact with either the operator or the customer.

Another and more detailed object of the present inveniton is to provide, in a device of this character, a novel heating element construction which is particularly adapted to maintain continuously a resistance value such as is necessary to give the desired heating qualities and the desired visibility of the heating element.

Other and more detailed objects and advantages of the invention will appear as the descrip" tion proceeds, reference being made to the accompanying drawing wherein a preferred form of the invention is shown. It is to be understood, however, that the drawing and description are illustrative only and are not to be considered as limiting the invention except insofar as it is limited by the claims.

In the drawing, Fig. 1 is a plan view of a heater clamp embodying the present invention;

Fig. 2 is an enlarged side View, partly in section, of the heater clamp;

Fig. 3 is an enlarged sectional view taken on the line 3-3 of Fig. 2; and

Fig. 4 is a detailed view illustrating the mounting of the heater element.

Referring now in detail to the drawing. the present invention is embodied in a permanent wave heating clamp of the type usually referred to as Croquignole heaters. The heater comprises two parts I0 and II which are hinged together by a hinge pin I2. Each part comprises a heater proper I3 and a handle portion I4. The two parts are duplicates and a detailed description of one will suflice for both. The handle element I4 is made of a suitable insulating material and is mounted on the heating element by an extended plate I5 and suitable screws I6 and IBa. The plate I5 extends from the handle and is concave as indicated at H to provide a heating surface for delivering heat to the hair. The peripheral edge of the curved portion I1 is curled over, as indicated at I8, to mount a cover I9. The cover I9 is of metal, as is the plate I5. The curved portion I! of the plate I5 is backed up by a concave sheet 20 which fits tightly against the portion I! to transmit heat to it. This plate 20 is preferably constructed of a metal of high heat conductivity such as aluminum. Between the plate 20 and the cover I 9, there is mounted a lining 2| of a good heat-insulating material such as asbestos in sheet form.

Electrical leads 22 and 23 are brought into the handle over the plate I5 to a recess 24 that is provided between the plate I5 and the extended portion 25 of the cover I9. Terminal wires 26 and 21 are extended from the conductors 22 and 23 through small porcelain tubes 28 and 29. The screw Ilia passes through a spacer block 30 which is interposed between the tubes 28 and 23 to hold them in position. The tubes 28 and 29, and the leads 26 and 21, are separated from the metal parts by a folded sheet of mica, indicated at 3I. This sheet of mica extends above the tubes 28 and 29 and extends between the leads 26 and 21 and the plate 20. The second sheet of mica, indicated at 32, extends below the tubes 28 and 28 and below the folded-over portion of the sheet 3|, so as to lie between this sheet and the plate 20. As shown best by Fig. 3, the sheet 32 is wider over the curved portion I1 than the sheet 3| and extends out to the lining 2| of asbestos, so as to prevent the leads from coming in contact with any metal in the interior of the heater.

The particular heating element structure which I have found to be essential to my invention, comprises a helically wound resistance element 33 which is particularly adapted to withstand high temperature heating by electric current without being affected as to its resistance value over a long period of time. The particular heating element used is a resistance wire containing iron, chomium, aluminum and cobalt, and now commercially available for heating unit purposes. I have found also that in order to obtain the practical results desired herein, the wire needs to be heated to a temperature substantially higher than normal for a few minutes. The temperature employed for this higher heat-- ing is 2000 to 2100 degrees Fahrenheit.

The heating element wound in helical form is wound spirally about a core 34 of ceramic material such as porcelain. The core 34 is grooved to receive the wire and hold the spirals thereof in spaced relation, the spirals being connected at the opposite ends of the resistance element to the terminal wires 26 and 21. Grooves 35 and 36 are provided in the core 34 for the terminal wires. The assembly of the core and the re-- sistance element is mounted in a sleeve 31, small plugs 38 and 39 being used to position the core 34 so that the resistance element 33 is spaced from the sleeve 31 throughout its length.

I have found that in a construction such as that employed here, the high heat of the resistance element and the enclosure of the glass sleeve makes it necessary to employ a glass sleeve of fused silica, or at least of high silica content, so as to be capable of withstanding the high heat generated by the heating element 33.

The heating element 33 is of such a nature that it glows brightly when in operation. I take advantage of this characteristic to provide the visibility necessary to enable the operator to see the heating element at all times. A small aperture 40 of elongated narrow shape is cut in the back of the cover I3, and a similar aperture 4| is cut in the asbestos lining 21. Where the sleeve 31 is of clear glass, this enables the operator to directly see the heating element through the aperture and thus determine whether or not it is operating and giving of! the bright glow that indicates full heating capacity. If desired, one may, of course, apply coloring, either in the form of a separate glass shield, or directly on the sleeve 31, at the aperture 40, to give a distinctive red warning signal.

The two units I0 and I I are pivoted on the pin I2 by means of ears 42 and 43 which are formed on the plates I5 of the units. A spring 44 is so wound about the pin I2 as to normally urge the concave portion I1 of the two units toward each other. In order to release the heater clamp, all the operator has to do is to press the handles I4 together.

It is believed that the foregoing description will be sufficient to enable those skilled in the art to construct and use the invention disclosed herein. The advantages of the invention are also believed to be readily apparent.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

A heater for hair waving comprising a heating element wound in a helix, said helix being wrapped upon a support of ceramic material, a glass sleeve in which said support is mounted, the sleeve being spaced from the heating element so as to avoid contact therewith, and a housing for said sleeve, said housing having a hair heating portion and a cover portion, the cover portion comprising an outer metallic sheet and an inner sheet of asbestos, and said cover portion having an aperture through which a portion of the glass sleeve and a portion of the heating element may be seen.

HARRY C. STEARNS. 

